Prior to the 1970's, no easy or affordable methods had been developed as a standard in the industry for obtaining comparative data on Loudspeakers to obtain. Approved laboratory tests were expensive and unrealistic for the thousands who needed performance information. Standard measurement criteria were needed to create consistent data for customers and allow comparisons between different speakers.
In the early XNUMXs several technical papers were published BEA (Audio Engineering Society). The development from this resulted in what we know today as the 'Thiele-Small parameter'. These papers were developed by ANThiele and Richard H. Small. Thiele was the senior design and development engineer for the Australian Broadcasting Commission and was at the time responsible for the Federal Engineering Laboratory, as well as analyzing designs for audio and video broadcast equipment and systems. Small was at the time a Commonwealth student at the School of Electrical Engineering at the University of Sydney.
Thiele and Small went to considerable lengths to show how the following parameters relate to a Loudspeakers and define a housing. However, they can be invaluable when choosing because they are far more real than the speaker Performance tell than the base sizes maximum power or average sensitivity.
This parameter is the free air resonant frequency of a Loudspeakers.
Simply put, it is the point at which the weight of the speaker's moving parts and the force of the speaker suspension in motion balance each other. If you've ever seen a twine
moving uncontrollably in the wind, you have already seen how the effect of resonant frequency occurs. It is important to know this information in order to prevent your case from ringing. With
one Loudspeakers, the mass of the moving parts and the stiffness of the suspension (bead and spider) are the key elements affecting the resonant frequency. As a general rule of thumb, the lower
Fs of a woofer, the better suited it is for low frequency reproduction than a woofer with a higher Fs. This is not always the case because other parameters affect ultimate performance as well.
DC resistance Re
This is the DC resistance of the driver, measured in Ohm with an ohmmeter and is also often referred to as 'DCR' or 'RDC'. This measurement will almost always be less than the nominal impedance (impedance). Buyers often become pensive when the Re is less than the impedance and worry
therefore the amplifier to overload. Due to the fact that the inductance of a loudspeaker increases with increasing frequency, it is unlikely that the amplifier will often have to work with DC resistance as its load.
Voice coil inductance Le
this is the voice coil Inductance measured in milliHenry (mH). The industry standard measures inductance at 1,000 Hz. As frequencies rise, so does the impedance across Re. This is because the voice coil acts as an inductor. Consequently, the impedance of a loudspeaker is not fixed Resistance, but can be represented as a curve that changes with input frequency.
The maximum impedance (Zmax) occurs at the resonant frequency (Fs).
Q - Parameters
Qms, Qes, and Qts are measurements related to monitoring cone suspension when the resonant frequency (Fs) is reached. The suspension must be designed to prevent any lateral movement that would otherwise result in contact between the voice coil and pole plate/Magnet would lead (this would result in the Loudspeakers destroy). The suspension must also act like a shock absorber.
Qms is a measure of the quality, which depends on the mechanical suspension (corner and spider) of the speaker. Think of this component as a spring. Qes is a measure of the quality that depends on the electrical suspension (voice coil and magnet) of the
speaker system. Qts is the measure of the overall quality of a driver and is derived from Qms and Qes.
The guideline is:
Qts of 0.4 or lower indicates a converter is well suited for vented enclosures.
Qts between 0.4 and 0.7 indicates that the Loudspeakers copes better in closed housings.
Qts of 0.7 or higher indicates that a converter is well suited for FreeAir or for "infinite" Sound wall.
As always, there are exceptions!
Equivalent volume Vas
Vas equals the volume of air that when compressed to a cubic metre, exerts the same force as that
Force (Cms) of suspension of a speaker. Vas is one of the most delicate parameters to measure because air pressure changes relative to humidity and temperature - so a tightly controlled laboratory environment is very important. VAS is given in liters. Cms is measured in meters per Newton. Cms is the force determined by the loudspeaker's mechanical suspension. It's simply a measurement of its stiffness. Looking at the stiffness (Cms), in connection
With the Q-parameters, one can make a comparison with a car manufacturer when they adjust the cars between comfort, for the promotion of the President or optimal performance in racing.
Now when you compare the peaks and valleys of an audio signal to a road surface, remember that the ideal speaker mount is like the suspension of a car. A car must be able to traverse the shakiest terrain with race car precision and the sensitivity of a fighter plane's speed. It's quite a challenge because if you focus on one discipline, another usually suffers.
membrane displacement volume Vd
This parameter indicates the maximum diaphragm displacement volume - in other words, the amount of air that the diaphragm can move. It is calculated by doubling Xmax (the distance the voice coil protrudes from the driver) and then multiplying by Sd (diaphragm area). Vd is given in cm³. The highest Vd value is desirable for an ideal sub-bass converter.
Force factor BxL or BL
Expressed in Tesla meters, this is a measurement of the driving force of a speaker.
Compare this to a good weightlifter. A certain mass will be on the Membran fastened and thus pushed back the membrane. It is measured how much current is required to move the membrane back to its original position.
The formula is mass in grams divided by current current in amperes.
A high BL value indicates a strong transducer that has control over the cone.
Moving Mass Mmd
This parameter is the combination of the weights of all mechanically moving parts of a woofer. The value consists of the weight of membrane + bead + spider + dustcap +Kitchen sink with carrier + pigtails together.
Effective mass moved Mms
This parameter is the combination of the weight of the membrane (= Mmd) plus the air mass on the membrane. Determining the weight of the membrane is easy: See above under "moved mass Mmd". Determining air mass is more complicated. In simple terminology, it is the weight of the air (the amount calculated in Vd) that the diaphragm has to move extra.
mechanical losses rms
NOT to be confused with the power specification Wrms!
This parameter represents the mechanical resistance caused by the suspension losses. It is a measure of the speaker suspension's absorption properties and is specified in N*s/m.
Efficiency Bandwidth Product EBP
This measurement is calculated by quotients of Fs to Qes. The EBP figure is used in many case designs to determine if a Loudspeakers more suitable is for a closed or ventilated housing. An EBP close to 100 usually indicates that a Loudspeakers is best suited for a ventilated enclosure. An EBP closer to 50 usually indicates that a Loudspeakers Together
is suitable for a closed housing. This is just a guide. Many well-designed systems have overturned this rule of thumb! Qts should also be taken into account.
Diaphragm stroke Xmax and Xmech
Xmax is a measure of the maximum linear deflection and is given in mm. Loudspeaker response becomes non-linear as the voice coil begins to exit the magnetic gap. Likewise, suspensions can have non-linearities
generate the playback. The point where the number of turns in the gap (see BL) decreases is the point where distortion increases. Xmax therefore indicates the path that the voice coil can cover in one direction without going below the number of turns in the effective magnetic gap.
Xmech is a measure of the maximum mechanical deflection and is also given in mm. There are four potential error conditions:
1. The spider tears due to overstretching
2. The voice coil hits the pole plate
3. The voice coil comes out of the magnetic gap
4. Physical limitations of the membrane
Take the lowest value of these measurements and multiply it by 2.
This gives a distance that describes the maximum mechanical movement of the membrane.
Membrane area Sd
This parameter indicates the effective membrane area in square centimeters.
Impedance Z (Zmax)
This parameter gives the apparent resistance (impedance) at Fs in ohms.
this is the frequency range, in which it makes sense to den Loudspeakers to use. Manufacturers use various techniques to determine transmission range. Most methods are accepted as acceptable in the industry, but different results are reached. Technically many will Loudspeakers used in areas that are theoretically of little use. Increasing frequencies reduces the off-axis radiance of a transducer relative to its diameter. At a certain point, the beam becomes 'beamy' or narrow like the beam from a flashlight. If you are in front of a Loudspeakers standing and then moving slightly to one side or the other, they noticed a change in the Klang. You have just experienced how this phenomenon works and you know what it is all about. Sure, most 2-way speakers ignore theory, and yet they play pretty well. But it's useful to know what limits they can compromise on.
Size Fmax
0.75″ 18,240Hz
1″ 13,680Hz
2″ 6,840HZ
3″ 5,472Hz
5″ 3,316Hz
6.5″ 2,672Hz
8″ 2,105Hz
10″ 1,658Hz
12″ 1,335Hz
15″ 1,052Hz
18″ 903Hz
performance pe
This specification is very important when choosing a converter. You must have one Loudspeakers choose one that is capable of handling the power your amplifier is delivering. It can be caused by too much or too little
want to print their individual Loudspeakers destroy. The ideal situation would be one Loudspeakers, who has the ability to take 10% more power than they can deliver. This gives them relative protection from thermal overload.
sensitivity / SPL
This data represents one of the most commonly used specifications for transducers. It's a representation of the value in use and the volume you can expect from it Loudspeakers relative to its power consumption. Loudspeakers Manufacturers follow various rules for obtaining this information - there is no exact standard accepted by the industry. As a result, as is often the case, the speaker buyer cannot compare this value when the sensitivities are designed differently by different manufacturers. The unit dB/W/m has developed as a standard.
There are manufacturers who specify their value as dB/W/0,5m in order to get a higher amount. Such values are
to be evaluated with due caution. Likewise values that refer to dB/2,83V/m.